1. Field of the Invention
The present invention relates to a vehicle height adjust control apparatus and method that maintains the vehicle height at a target vehicle height.
2. Description of the Related Art
In a vehicle height adjust control apparatus that adjusts the vehicle height so that the vehicle height is maintained at a target vehicle height, as described in, for example, Japanese Patent Application Laid-Open Nos. SHO 58-36712 and 58-36713, the vehicle height changing control is allowed when the vehicle acceleration in the fore-to-aft direction or a lateral direction is less than a predetermined value, and the vehicle height changing control is prevented when the vehicle acceleration becomes greater than the predetermined value.
Such an apparatus allows a certain reduction of the frequency of the performance of vehicle height adjustment in response to a temporary change in the vehicle height at various portions of the vehicle body which is caused by a change in the vehicle acceleration in the for-to-aft or lateral direction. If the predetermined value used for the determination regarding the acceleration is set to a reduced value, the frequency of the suspension and restart of vehicle height adjustment increases. Conversely, if the predetermined value is set to an increased value, the frequency of the performance of vehicle height adjustment caused by a change in the acceleration cannot be reduced. In either case, the frequency of actuator switching operations increases, so that the incidence of noises produced during the switching of actuators increases. Moreover, the durability or service life of the actuators decreases due to the frequent actuator switching operations.